1. Field of the Invention
This invention relates broadly to analytical instruments. More particularly, this invention relates to an incubation system for an analyzer apparatus.
2. State of the Art
A number of analysis systems require that a test sample under analysis be brought to and held at a desired temperature during analysis. For example, water test kits are used to determine the bacteriological activity within water. According to some kits, a water sample is taken in an ampoule and the ampoule is held at 35xc2x0 C. Only at the required temperature will the growth of the bacteria be constant so that the sample can be analyzed with light to determine bacteriological content. In the field, some products require that the sample be brought to the required temperature by keeping the ampoule in an inside shirt pocket of the user performing the test. However, this is inexact and inconvenient.
While the prior art does include incubators for other analysis systems, such existing incubators have a number of serious drawbacks. First, many incubators adapted to heat to a particular temperature are quite complex which results in high cost.
Second, complex devices are often bulky. The bulk reduces the portability of the device and inhibits the use of such a device in the field.
Third, incubation systems often require calibration. However, calibration typically requires the use of expensive and adjustable components such as error-prone trim potentiometers or ultra high precision components. Moreover, the adjustment of such components requires the time of the operator and introduces human error.
Fourth, many systems do not permit sample ampoule heating while under analysis. For example, in U.S. Pat. No. 3,877,817 to Ralston, after an ampoule is heated to a desired temperature in a heating compartment, it is then transported to a measuring compartment for analysis as the light source of the light analysis portion of the Ralston system adversely affects proper stabilized heating of the sample ampoule.
It is therefore an object of the invention to provide an apparatus which maintains ampoules at a desired temperature.
It is another object of the invention to provide an incubation system which is self-calibrating.
It is also an object of the invention to provide a portable and relatively low cost apparatus for heating ampoules.
It is a further object of the invention to provide an apparatus which accurately heats ampoules in the same location at which they are analyzed.
In accord with these objects, which will be discussed in detail below, an ampoule incubator and light analyzer is provided which includes a housing having at least one receptacle (or nest) for an ampoule, a cover for substantially preventing ambient temperature and light from affecting each receptacle, an incubation system, a light analysis system, and a master control system. The incubation system includes, for each receptacle, a heating element which heats the receptacle and a temperature sensor which senses the temperature of the receptacle. Each receptacle is preferably insulated to prevent unintended heating of neighboring receptacles of the apparatus. The light analysis system includes, for each receptacle, at least one light source and a photodetector positioned such that the light from the light source passes through the receptacle (and thereby the ampoule and its contents) prior to entering the photodetector.
The master control system permits user input, operates the incubation system and the light analysis system, and provides a user-readable display for the output of the results of the light analysis of the contents of the ampoule in the receptacle.
According to a preferred aspect of the invention, the incubation system is adapted to quickly heat the receptacle (and consequently the ampoule provided therein) up to the desired temperature. The incubation system is calibrated by soaking the receptacles and associated components including the temperature sensor, all in a powered state on a circuit board, in a controlled temperature environment maintained at the desired operation temperature for analysis of the ampoules, for example, at 35xc2x0 C. When the receptacles and associated components are at the desired operation temperature, switches are closed causing a microcontroller of the master control system to store digital representations of the temperature of each individual receptacle in non-volatile memory. Then, during operation of the apparatus, the incubation system is directed to the values previously set in the non-volatile memory during calibration, without necessitating expensive and adjustable components such as error-prone trim potentiometers or ultra high precision components, or human intervention during use.
The apparatus may include a large number of receptacles suitable for laboratory use or may include fewer or one receptacle suitable for home or portable use.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.